Driving motion for loom dobbies



E. R. HOLMES DRIVING MOTION FOR LOOM DOBBIES Aug. 17, 1937.

Filed Feb. 4, 1937 2 Sheets-Sheet 1 Inventor EWvidqe R. Hoknes Attorney Aug. 17, 1937.

Filed Feb. 4, 1937 E. R. HOLMES 2,090,047

DRIVING MOTION FOR LOOM DOBBIES 2 Sheets$hee t 2 a" lahlllllllllll Patented Aug. 17, 1937 UNITED STATES PATENT OFFICE DRIVING MOTION FOR LOOM DOBBIES Application February 4, 1937, Serial No. 124,146

9 Claims.

This invention relates to improvements in loom dobbies and it is the general object of the invention to provide a dobby drive wherein the time of operation of the dobby parts is the same on suc- 5 cessive beats of the loom.

In the ordinary dobby loom a crank on the bottom shaft is connected to a lifter rod the upper end of which is attached to a three-arm rocking lever which reciprocates the harness lifting knives. The rod moves fastest when it is at right angles to the crank, or tangent to the circle in which the crank rotates. The points of tangency are both above the bottom shaft, hence the crank when rising from extreme low position must turn through more than to give the rod its maximum speed, but when descending from high position the rod attains its highest speed before the crank moves 90. There necessarily results an unevenness in the time of harness crossing on successive beats of the loom.

It is an important object of my present invention to provide a drive for the dobby wherein the time of operation of the dobby parts will be the same on two successive beats of the, loom and Whether the crank be moving up or down. This result I achieve as set forth hereinafter by means of planetary gearing including a fixed solar gear around the axis of the bottom shaft and a planet gear carried on a crank arm moving with the bottom shaft and connected to the dobby lifter rod.

It is a further object of my present invention to provide a mechanism wherein the bottom of the lifter rod may be caused to rise and fall along a vertical line passing through the axis of the bottom shaft and having the same amount and character of motion whether the planet gear be above or below the bottom shaft. This result I achieve by having the pivotal connection between the lifter rod and the planet gear on the axis of the bottom shaft when the crank is horizontal or on the pitch line of the planet gear.

It is occasionally desirable to vary the cycle of harness motion with respect to the loom cycle and in order to accomplish this result it is a further object of my invention to provide a solar gear which can be given an angular adjustment around the axis of the bottom shaft. Because of this arrangement it is possible to vary the angular relation between the crank arm which carries the planet gear and the line joining the pivots of the planet gear and lower end of the lifter rod. When it is desired to have one-half of the harness shifting cycle completed when the lay is on front center the crank arm and the line joining the pivots of the planet gear and lifter rod will be parallel, but when it is desired to have more or less than one-half of the harness cycle completed when the lay reaches front center the solar gear is changed so that the line joining the pivots of the planet gear and lifter rod is oblique with respect to a horizontal when the crank arm is horizontal.

With these and other objects in View which will appear as the description proceeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawings, wherein a convenient embodiment of my invention is set forth,

Fig. 1 is an end elevation of a loom having my invention applied thereto,

Fig. 2 is a rear elevation taken in the direction of arrow 2, Fig. 1,

Fig. 3 is a detailed section on an enlarged scale on line 33, Fig. 1, 20

Fig. 4 is an end elevation showing the planet gear on an enlarged scale,

Figs. 5 to 8 are diagrammatic views showing the planet gear in four different positions with respect to the bottom shaft, and 25 Fig. 9 is a view similar to Fig. 8 but with the mechanism set to give a greater lift to the harness.

Referring particularly to Figs. 1 and 2, I have shown a loom framev ll] having a dobby D provided with a lever l I having top and bottom arms 12 and I3, respectively, which drive top and bottom knives l4 and I5, respectively. A laterally extending arm 16 of the lever II is connected as at ll to the upper end of a lifter rod l8 which is reciprocated vertically by mechanism to be described and forming the subject matter of my present invention. The knives are caused to engage hooks IS by means of pattern mechanism not shown and dobby levers 20' are rocked, depending upon which of the hooks are moved outwardly or to the right as viewed in Fig. 2 by the knives. Each lever 20 is connected to a harness jack 2| which may be attached in usual manner to the harness frames of the loom not shown.

The lay 25 is driven by connector 26 of the top shaft 21 to move the lay back and forth in the loom so that it passes through front and back center positions for each revolution of the top shaft. The bottom shaft 28 is geared to the top shaft so that it makes one revolution for every other revolution of the top shaft by gearing indicated' at 30.

The parts thus far described are of common construction and of themselves form no part of my present invention. The lever ll rocks about 55 its pivot 25 first to the right and then to the left,

each rocking moving one knife outwardly and the other knife inwardly and two successive rockings of the lever being required to complete the two pick cycle of the dobby.

In carrying my present invention into effect I provide an auxiliary stand 40 having a bearing 4| for the extended end 42 of the bottom shaft. Bolts 43 extend through slots 44 in stand 40 and are tapped into solar gear 45 to secure the latter to the stand 4!! in any one of the plurality of angular positions with respect to the bottom shaft. The gear 45 has internal teeth 46 which are held stationary and mesh with the teeth of a 5 planet gear 4']. The latter is mounted on a stud 48 carried by a crank arm 49 secured in adjusted angular position on the bottom shaft by means of set screws 58.

By referring to Fig. 4 it will be seen that the planet gear has integral therewith a radial arm 55 having a slot 55 to receive a bolt 51. The latter has a head 58 which is retained by top and bottom parallel ribs 5.9 integral with the arm 55, see Fig. 3. A bushing 55 surrounds the bolt and has a shoulder 6| which is held against the ribs 59 by means of a nut 62 on the bolt. A washer 63 may be located between the nut and the bushing and the latter has pivotal connection with a rod head 64 pivoted at 65 to the lower end of lifter rod l8. By loosening the nut 62 the bolt may be slid along the slot 56 any desired distance from the center of the planet gear.

In operation, the bottom shaft will turn in a clock-wise direction or in the direction of arrow a, Fig. 1 and the arm 49 will rotate around the axis of shaft 28, carrying the stud 48 and therefore the planet gear 4'! bodily around the bottom shaft. Since the solar gear is stationary, rotation of the crank arm 49 will cause the planet 4 gear to rotate on its axis in a counter-clockwise direction as viewed in Fig. 1.

Assuming that the knives are in their extreme positions with the lifter rod up, the planet gear will be in the position shown in Fig. 5 and the 45 arm 55 will be vertical. The stud 51 is therefore at its highest position above the bottom shaft and lever II is in one extreme position. As the bottom shaft continues to rotate the stud 48 will assume a position horizontally to the right of the bottom shaft as indicated in Fig. 6. The planet gear has half the number of teeth of the solar gear and that part of the planet gear which is diametrically opposite the arm 55, being 180 removed from said arm along the pitch line of the planet gear, will have moved to a position on the solar gear 90 removed from the position of Fig. 5 to that of Fig. 6. This results in a downward motion of the stud 51. As shown in the drawings stud 51 is set to be in alignment 0 with the axis of the bottom shaft when the parts are in the position of Fig. 6.

Furtherro-tation of the bottom shaft to place the axis of the planet gear under the bottom shaft and arm 55 will hang vertically down, as

65 shown in Fig. 7, while still further rotation of the bottom shaft will place the planet gear to the left of the bottom shaft to turn the arm 55 horizontally to the right, or as shown in Fig. 8. It will be seen that when the parts move from 70 the position of Fig. 5 to that shown in Fig. 7 stud 51 moves down along a substantially straight line, and when the parts move from the position of Fig. 7 through Fig. 8 and back to the position of Fig. 5, stud 51 ascends along a simi- 1ar line. Since the crank arm 49 rotates uniof the bottom shaft.

formly with the bottom shaft the stud 51 hasv an even motion both above and below the bottom shaft and the knives are therefore equally timed with respect to the loom cycle on successive beats of the lay.

When the construction, set forth hereinbefore is to be used with dobbies requiring a greater lift of the harnesses, pivotal connection I! will be moved along slot 15 in the arm it toward axis 29. When such an adjustment is insufficient to give the requisite angular motion to lever II, however, I may move the stud 5? along the arm 55 away from the stud 48 to some such position as indicated at E5 in Fig. 9, wherein the stud is indicated as being out of alignment with the axis With such a setting stud 5! will move along an elliptical path, as indicated in dotted, line c, Fig. 9 and the high and low positions of stud 57 will exceed those su gested by Figs. 5 and 7. The path traversed by the stud 5'! under these conditions is that of an elongated ellipse the major axis of which is the total lift of the stud 5'! and the minor axis of;

which is double the offset of stud 5'? with respect to the axis of the bottom shaft. It is found, however, that the time of operation of the knives on two successive beats of the loom. is substantially the same, the ellipticity of the path traversed by stud 57 having no appreciable effect on the character of motion of the lifter rod.

From the foregoing it will be seen that I have provided a simple type of planetary gearing to drive the knives of a dobby with equal time. While the invention has been described in connection with a dobby yet I do not consider that its application is necessarily restricted to a shedding mechanism of that particular type. It will be noted that the motion includes a stationary internal solar gear meshing with a planet gear which rotates about a driving shaft within the solar gear, and that the connections with the lifter rod give the lower end of the latter a reciprocating motion along a rectilinear line. It will further be seen that when greater lift of the rod 58 is desired the stud 57 can be moved out,

of alignment with the axis of the bottom shaft and that the resultant elliptical path traversed by the stud does not materially affect the timing.

of the dobby. Also, the cycle of harness motions can be changed relatively to loom time by altering the angular position of the solar gear.

Having thus described my invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but what I claim is:

1. In a dobby loom, a rockable knife driving lever, a connector therefor, a rotating shaft, a stationary solar gear concentric with the shaft, a planet gear within and meshing with the solar gear, means to connect the planet. gearto the shaft and cause said gear to move in a path around the axis of the shaft, and means to attach the planet gear to the connector.

2. In a dobby loom, a rockable knife'driving lever, a connector therefor, a rotating shaft, a stationary solar gear having internal teeth concentric with the shaft, a planet gear of half the diameter of the solar gear located within the latter and meshing with the teeth thereof, means to mount the planet gear on the shaft and cause the center of the planet gear to revolve in a path the planet gear to the connector.

3. In a dobby loom, a rockable knife driving lever, a connector therefor, a rotating shaft, a stationary solar gear having teeth concentric with the shaft, a planet gear of half the diameter of the solar gear within and meshing with the teeth of the solar gear, an arm mounted on and rotating with the shaft, means to support the planet gear on the arm with the axis of said planet gear at a distance from the axis of the shaft, and means to attach the connector to the planet gear.

4. In a dobby loom, a rockable knife driving lever, a connector attached to the lever to rock the latter, a stationary solar gear having internal teeth, a planet gear located. within the solar gear and meshing with the teeth thereof and being half the diameter of the solar gear, means to cause the center of the planet gear to move in a path concentric with the axis of the solar gear, and means to attach the planet gear to the connector.

5. In a dobby loom, a rockable knife driving lever, a connector attached to the lever to rock the latter, a stationary solar gear having internal teeth, a planet gear located within the solar gear and meshing with the teeth thereof and being half the diameter of the solar gear, means to cause the center of the planet gear to move in a path concentric with the axis of the solar gear, attaching means toconnect the planet gear to the connector at a point in alignment with the axis of the solar gear, to the end that rotation of the planet gear bodily about the axis of the solar gear will cause the attaching means between the planet gear and the connector to reciprocate in a substantially straight line.

6. In a dobby loom, a rockable knife driving lever, a connector therefor, a rotating shaft, a stationary solar gear concentric with the shaft, a planet gear within and meshing with the solar gear, means to connect the planet gear to the shaft and cause said gear to move in a path around the axis of the shaft, means to attach the gear to the connector, and means to give the solar gear a plurality of fixed angular positions around the axis of the shaft to vary the cycle of movements of the connector relatively to the time of the shaft.

'7. In a dobby loom, a rockable knife driving lever, a connector attached to the lever to rock the latter, a stationary solar gear having internal teeth, a planet gear located within and meshing with the teeth of the solar gear and being half the diameter of the solar gear, means to cause the center of the planet gear to move in a path concentric with the axis of the solar gear, and means to attach the planet gear to the connector, said last named means including an arm moving with the planet gear and having provision for attaching the connector to said arm at a plurality of points at different distances from the axis of the planet gear.

8. In a dobby loom, a rockable knife driving lever, a connector attached to the lever to rock the latter, a stationary solar gear having internal teeth, a planet gear located within and meshing with the teeth of the solar gear and being half the diameter of the solar gear, means to cause the center of the planet gear to move in a path concentric with the axis of the solar gear, and means to attach the planet gear to the connector, said last named means including an arm rigid with the planet gear and having a slot in which is located a pivot element to be connected to the connector, said pivot element capable of being located at a plurality of points at diiferent radial distances from the axis of the planet gear.

9. In a loom dobby, a rockable knife driving lever, a connector attached to the lever to rock the latter, a stationary solar gear having internal teeth, means to hold the solar gear in any one of a plurality of angular positions around the axis thereof, a planet gear located in the slot within and meshing with the teeth of the solar gear and being half the diameter of said solar gear, means to cause the center of the planet gear to move in a path concentric with the axis of the solar gear, an arm moving with the planet gear and having a slot therein, and a pivot element for the connector to be located in a plurality of positions fixed with respect to the arm and at different positions from the axis of the planet gear, the solar gear to have the angular position thereof changed to Vary the cycle of movements of the slotted arm and connector relatively to the time-of the means which causes the planet gear to move in said concentric path and said pivot element to be changed relatively to the axis of the planet gear to vary the extent of motion of the connector.

ELBRIDGE R. HOLMES. 

